There has been a type of portable terminal including contact sensors on opposite side surfaces of a casing. An example of such portable terminals is a portable terminal disclosed in Patent Literature 1. This portable terminal is configured as follows: The entire region of each of the contact sensors is divided into a plurality of sensor regions. The portable terminal determines, on the basis of the number of ON signals supplied for each sensor region, the number of fingers (thumb) touching each contact sensor. The portable terminal performs different processes in correspondence with the determined number of fingers (thumb). This configuration allows for an increase in the number of determinable patterns of how the casing is being held.